Rice, Morgan W.

Background: Outcomes after arthroscopic rotator cuff repair (RCR) are frequently measured through clinically significant outcomes (CSOs) such as the minimal clinically important difference, the substantial clinical benefit, and the Patient Acceptable Symptom State. Global achievement of CSOs is challenging to predict. Purpose: To determine if unsupervised machine learning can identify distinct patient subgroups based on CSO achievement after elective arthroscopic RCR. Study Design: Case-control study; Level of evidence, 3. Methods: A prospectively collected database was analyzed to identify patients who underwent elective arthroscopic RCR from 2015 to 2017. Tear dimensions were measured on magnetic resonance imaging utilizing a validated technique. CSO achievements on the American Shoulder and Elbow Surgeons, the Single Assessment Numeric Evaluation, and the Constant-Murley subjective score at 2-year follow-up were calculated. An unsupervised random forest algorithm was utilized to develop and internally validate patient subgroups with significantly different rates of CSO achievement. Patient subgroup membership, along with a total of 30 demographic and clinical variables, as well as preoperative patient-reported outcomes, were incorporated into a stepwise multivariable logistic regression to identify factors predictive of optimal CSO achievement. Results: A total of 346 patients (192 male; mean ± SD age, 57.2 ± 9.1 years; body mass index, 30.1 ± 5.4 kg/m 2 ) were eligible for inclusion and followed for a mean of 3.8 years (range, 2.0-6.2 years) Of these, a total of 333 patients were partitioned by the random forest algorithm into 2 subgroups (stability, 0.16; connectivity: 180.8; Dunn: 0.16; silhouette: 0.05), with 176 patients in the optimal achievement subgroup and 157 patients in the suboptimal achievement subgroup. The 2 subgroups differed significantly (all P ≤ .004) in the likelihood of achievement of all CSOs. Stepwise multivariable logistic regression identified an increase of 1 mm in tear size in the sagittal dimension beyond 1.9 cm to predict a 10% increase in the probability of suboptimal achievement. Additional risk factors for suboptimal CSO achievement included increasing number of tendons involved (odds ratio [OR], 14.07; 95% CI, 4.50-44.02; P < .001), subscapularis involvement (OR, 8.67; 95% CI, 2.45-30.71; P = .01), and increased preoperative CMS score (OR, 1.11; 95% CI, 1.04-1.18; P = .001). Protective factors included performance of a subpectoral biceps tenodesis compared with biceps tenotomy (OR, 0.22; 95% CI, 0.05-0.92; P = .03). Conclusion: Clinically meaningful subgroups were uncovered using an unsupervised machine learning algorithm in patients undergoing arthroscopic RCR. Tear size, number of tendons involved, and subscapularis involvement were significant and additive predictors of suboptimal CSO achievement at 2-year minimum follow-up. Treatment of concurrent biceps pathology with tenodesis conferred 78% increased likelihood of CSO achievement compared with tenotomy.

Background: Femoral torsion measurements and outcomes are variable throughout the literature and have focused on short-term follow-up. However, there is a paucity of literature investigating clinically meaningful outcomes at midterm follow-up after hip arthroscopy for femoroacetabular impingement syndrome (FAIS). Purpose: To quantify femoral version using computed tomography imaging in patients with FAIS and to explore the relationship between version abnormalities and 5-year outcomes after hip arthroscopy. Study Design: Cohort study; Level of evidence, 3. Methods: Patients who underwent primary hip arthroscopy for FAIS between January 2012 and November 2017 were identified. Patients were included if they had 5-year follow-up with completion of ≥1 patient-reported outcome (PRO) scores and excluded if they had Tönnis grade >1, revision hip surgery, a concomitant hip procedure, a developmental disorder, or a lateral center-edge angle <20°. Torsion groups were defined as severe retrotorsion (<0°), moderate retrotorsion (0.1°-5°), normal torsion (5.1°-20°), moderate antetorsion (20.1°-25°), and severe antetorsion (>25.1°) based on computed tomography measurements. Patient characteristics were analyzed among the torsion cohorts, as were preoperative and 5-year PROs: Hip Outcome Score–Activities of Daily Living, Hip Outcome Score–Sports Subscale, modified Harris Hip Score, international Hip Outcome Tool, visual analog scale for pain, and visual analog scale for satisfaction. Achievement rates of cohort-specific thresholds for the minimal clinically important difference and Patient Acceptable Symptom State were calculated and compared among cohorts. Results: A total of 362 patients (244 female, 118 male; mean ± SD age, 33.1 ± 11.5 years; body mass index, 26.9 ± 17.8) met inclusion/exclusion criteria and were analyzed at a final mean follow-up of 64.3 ± 9.4 months (range, 53.5-115.5 months). Mean femoral torsion was 12.8°± 9.2°. The number of patients within each group was 20 for severe retrotorsion (torsion, −6.3°± 4.9°), 45 for moderate retrotorsion (2.7°± 1.3°), 219 for normal torsion (12.2°± 4.1°), 39 for moderate antetorsion (21.9°± 1.3°), and 39 for severe antetorsion (29.0°± 4.2°). No significant differences in age, body mass index, sex, smoking status, workers’ compensation, psychiatric history, back pain, or physical activity were found among the torsional groups. All groups demonstrated significant improvements at 5 years postoperatively ( P < .01 for all). All torsion subgroups demonstrated similar pre- to postoperative changes in PROs ( P≥ .515) and PRO values at 5-year follow-up ( P≥ .098). There were no significant differences in the achievement of the minimal clinically important difference ( P≥ .422) or Patient Acceptable Symptom State ( P≥ .161) for any of the PROs among the torsion groups. Conclusion: The orientation and severity of femoral torsion at the time of hip arthroscopy for FAIS in this study’s cohort did not affect the propensity for clinically meaningful outcome improvement at midterm follow-up.

Purpose To determine whether (1) patient‐reported outcome (PRO) scores after index hip arthroscopy correlate with PRO scores for the contralateral hip in patients undergoing staged bilateral hip arthroscopy and (2) patients who achieved minimal clinically important difference (MCID) or patient‐acceptable symptom state (PASS) for the index hip were more likely to achieve MCID or PASS for the contralateral hip. Methods Patients who underwent staged bilateral hip arthroscopy for femoroacetabular impingement syndrome were retrospectively reviewed. PRO scores were prospectively collected at preoperative and 1‐ and 2‐year timepoints. Odds ratios for achievement of MCID and PASS for the contralateral hip given achievement for the index hip were calculated. Improvements from before surgery to 2 years after surgery were correlated between both hips. Results A total of 143 patients (286 hips) were included in the final analysis. Average time between surgeries was 8.5 months (range, 0.7‐57.2). Both hips demonstrated significant improvement ( P < .05 for all) in all PROs at 2 years. Achievement of MCID in Hip Outcome Score Activities of Daily Living (HOS‐ADL) at the 1‐year timepoint for the index hip was predictive of achievement of MCID in HOS‐ADL at 2 years for the contralateral hip. Achievement of PASS in all PROs at the 1‐year timepoint for the index hip were predictive of achievement of PASS in the equivalent outcome score at the 2‐year mark for the contralateral hip. Achievement of MCID or PASS at the 2‐year timepoint for the index hip was predictive of achievement of the equivalent outcome at the 2‐year timepoint for the contralateral hip. The strongest correlation between improvement in PRO scores for the index and contralateral hips was noted in patients who underwent staged hip arthroscopy within less than 3 months. Conclusion Patients experience significant clinical benefit in both hips after staged bilateral hip arthroscopy. Results from the initial hip arthroscopy at either 1‐ or 2‐year follow‐up can be used to predict outcomes on the contralateral side; however, there is a higher degree of predictive value using 2‐year results. Average correlations between 2‐year PROs on the index and contralateral hips were moderate to strong, regardless of the time between surgeries. Level of Evidence Level III, retrospective cohort study.